Corrosion Services: Preventing Corrosion
We’ve discovered more than a few effective methods for protecting steel from corrosion. Some methods have been in use for longer than others, some are better for the environment than others, and all of them entail certain tradeoffs as far as performance, price and material properties are concerned.
The corrosion services you receive need to reflect the conditions your assets endure. Environmental factors such as acid rain, humidity, chemical salts, oxygen and high temperatures are all factors that can affect the pace of corrosion. It’s best to control for these factors where possible, but this is often impractical or downright impossible. For more reliable methods of corrosion prevention, more active solutions are called for.
While many methods of corrosion prevention have been tested out over the years, a couple of them have emerged as among the most effective. Corrosion resistant coatings are among the most reliable and cost-effective methods for fighting corrosion. For reasons of chemistry, coating structural steel in gold would probably be fairly effective in protecting it from corrosion. But for more obvious reasons, this is not a widely used method of corrosion control.
Within the realm of protective coatings, a few strategies have emerged as particularly effective corrosion services. It’s no coincidence that two of them, barrier and sacrificial coatings, are among the coating services that we specialize in.
Here’s a top-level breakdown of the strategies most of our products use to battle corrosion:
Sacrificial coatings tend to make excellent primers. These unselfish coatings usually take the form of an extremely thin layer of metal, such as zinc or nickel, which is known to corrode preferentially to steel. These coatings are applied directly to a ferrous metal, usually steel, in order to steer the corrosion process in a direction that is ultimately not harmful to the asset by “donating” an electron to the substrate to make its charge unfriendly to the corrosion process.
Zinc primers are excellent examples of sacrificial coatings. Though they’re meant to corrode preferentially to the asset, the rate at which they succumb to corrosion is slower than many other sacrificial coatings, leading to longer intervals before a recoat is necessary.
When combined with a topcoat system that offers excellent barrier properties, sacrificial primers form part of a system with proven success in fighting corrosion.
Barrier coatings are probably the products that come to mind when most people think of industrial coatings. These are the products in charge of keeping oxygen and moisture from a substrate and protecting it from harmful chemicals, including soluble salts.
According to NACE, the following are the most important properties for a barrier coating. A coating should:
- Be able to protect from the surrounding chemical environment
- Be able to resist moisture
- Be able to resist vibration and minor impacts
- Exhibit strong adhesion properties even in moist conditions
- Exhibit strong wetting properties for a smooth, even film build
Different environments stress barrier coatings in different ways. In areas experiencing prolonged exposure to sunlight, a high UV-resistant coating will be a priority. In marine environments, a coating’s ability to protect against soluble salts and their corrosive effects will be especially important. In chemical factories and other processing facilities, where harsh and reactive materials are an everyday reality, good chemical resistance will be a necessary property.
Given the wide array of elements barrier coatings must protect against, it’s a good thing they’re not working alone. When combined with a sacrificial primer, and sometimes an intermediate barrier coating, a good barrier coating is part of a system that effectively fights corrosion.
But it’s important to know exactly which system is called for given an asset’s environmental circumstances. That’s why we offer on-site surveys as part of our corrosion services.